This lesson follows the lesson on food chains where students learned about the flow of energy in an ecosystem. Today, students will learn about the energy lost between trophic levels. Students will be challenged to engage in critical thinking by being posed with this question, “A small group of people are stranded on a barren desert island. They have 500 bushels of wheat and one cow. What should they do to survive for the greatest length of time?”
Several options will be presented to them. Students will choose the response they think is best and attempt to rank all of the responses. Students must give written reasons to justify their rankings. There will be a class discussion about how students ranked their options. Then, new information will be given about trophic levels and energy loss. Students will then be asked to reconsider their rankings in light of the new information presented to them. Students will then discuss reasons for these new rankings. Students will complete the Trophic level and Energy pyramids worksheet and hand it in at the end of class.
Objectives:
Students will be able to…
Use critical thinking skills by working in groups to try to resolve a problem
Use evidence to support a claim
Identify what trophic level an organism belongs in
Create an energy pyramid
Calculate how much energy is in each trophic level if given the energy at one level
Students should have premade groupings in order to avoid loss of instructional time and to avoid bickering about who is in each group.
Instruction
Opening (5-10 min)
“Yesterday we dissected owl pellets and designed a food chain depicting all of the different plants and animals that had to be eaten before they became part of the owl’s diet.
Which way does energy flow in a food chain or web?
Do you think any energy is lost on its way up the food chain?
How much energy do you think actually makes it from the bottom of that food chain or web all the way up to the owl?
“Today I’m going to present you with a question that could potentially help save your life someday. I want you to really think about what you would do in this situation to help yourself survive the longest.”
Activity (25-30 min)
Students will get into their predetermined heterogeneous groups of 4 to discuss the question. While the students are in getting into their groups, I will pass out the large poster paper (one for each group), and markers. I will put the question and the answer options on the overhead projector. Students will debate about the best way to rank the answers and they will write their rankings on the poster paper. At the bottom of the paper, they will give their reasons for the way they ranked the responses.
When they are finished ranking, each group will share out their ranking and give an explanation as to why they decided to rank them that way. I will write each ranking on the board so that we can compare all the groups.
Next I will introduce new information by playing a short video about the 10% in an ecosystem. We will discuss and review terms from yesterday’s lesson.
What is a producer? Consumer?
What kinds of orgainsms are producers? Consumers?
What is a trophic level?
In what trophic levels are producers/consumers found?
Then I will ask students to re-rank their answers in light of their new understanding of energy flow in ecosystems. We will again share out rankings and the new reasons for the rankings. Then I will begin closing.
Closing (15 minutes)
How many of you changed your rankings today after we discussed energy loss?
Who wants to come up to the board and draw out the energy pyramid containing the wheat, the cow, and the people?
Who is the producer? Primary consumer? Secondary consumer?
If the wheat had 10,000 calories in it, how much energy would have made it to you if you had let the cow eat the wheat before you ate the cow?
How much if you had just eaten the wheat?
Besides the energy loss between trophic levels, what other things might you consider when approaching this question? (Looking for cow is alive and burning calories).
In this example, we only really looked at 3 trophic levels. In reality, most ecosystems only have a few trophic levels. What do you think is the reason for this?
Please finish all of the questions in your worksheet and hand them in before leaving class today.
Assessment
Questions during activity, answers on poster paper, Trophic Level and Energy Pyramid Worksheet.
Overview:
This lesson follows the lesson on food chains where students learned about the flow of energy in an ecosystem. Today, students will learn about the energy lost between trophic levels. Students will be challenged to engage in critical thinking by being posed with this question, “A small group of people are stranded on a barren desert island. They have 500 bushels of wheat and one cow. What should they do to survive for the greatest length of time?”
Several options will be presented to them. Students will choose the response they think is best and attempt to rank all of the responses. Students must give written reasons to justify their rankings. There will be a class discussion about how students ranked their options. Then, new information will be given about trophic levels and energy loss. Students will then be asked to reconsider their rankings in light of the new information presented to them. Students will then discuss reasons for these new rankings. Students will complete the Trophic level and Energy pyramids worksheet and hand it in at the end of class.
Objectives:
Students will be able to…
Materials
Preperation Notes
Instruction
Opening (5-10 min)
“Yesterday we dissected owl pellets and designed a food chain depicting all of the different plants and animals that had to be eaten before they became part of the owl’s diet.
“Today I’m going to present you with a question that could potentially help save your life someday. I want you to really think about what you would do in this situation to help yourself survive the longest.”
Activity (25-30 min)
Students will get into their predetermined heterogeneous groups of 4 to discuss the question. While the students are in getting into their groups, I will pass out the large poster paper (one for each group), and markers. I will put the question and the answer options on the overhead projector. Students will debate about the best way to rank the answers and they will write their rankings on the poster paper. At the bottom of the paper, they will give their reasons for the way they ranked the responses.
When they are finished ranking, each group will share out their ranking and give an explanation as to why they decided to rank them that way. I will write each ranking on the board so that we can compare all the groups.
Next I will introduce new information by playing a short video about the 10% in an ecosystem. We will discuss and review terms from yesterday’s lesson.
Then I will ask students to re-rank their answers in light of their new understanding of energy flow in ecosystems. We will again share out rankings and the new reasons for the rankings. Then I will begin closing.
Closing (15 minutes)
Please finish all of the questions in your worksheet and hand them in before leaving class today.
Assessment
Homework
References
Shields, Martin. 2005. Biology Inquiries: Standards-Based Labs, Assessments, and Discussion Lessons.
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